Sociedad Europea de Análisis Diferencial de Movilidad

SEADM

Differential Mobility Analyzer (DMA)

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COMPANY OVERVIEW

• SEADM is a Spanish SME founded in 2005, whose aim is to become a centreof excellence in the field of analytical instrumentation for the analysis oftrace elements and nanoparticles, based upon the know-how of co-founderand Technical Consultant Juan Fernandez de la Mora

• In the most recent and complete literature review on the integration of IMSand MS techniques, SEADM was cited as the generator and owner of two ofthe six most relevant current techniques, the TM-IMS and the DMA [Clemmeret Al., J. Chromatography A, 1439, 2016, 3-25] .

• Main company technology is actually Differential Mobility Analysis, uponwhich it holds 9 patents.

• SEADM’s Differential Mobility Analyzers can be used in a stand-alone basis orin combination with a mass spectrometer for thorough 2D analytical studies.Range of applications is very broad and include atmospheric science,nanoparticle formation, nucleation studies, proteomics, polymers, etc.

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DIFFERENTIAL MOBILITY ANALYZER

• Resolving power up to 110 (laminar flow even at Re> 200,000)

• Continuous ion sampling / high duty cycle

• Ion transmission up to 50%

No special preparation of samples

Low qualification personnel

High degree of automation

Quick analysis (2 minutes)

• Physical principle

Same principle applies for the axisymmetric DMA Planar DMA

The Differential Mobility Analyzer, DMA, is a peculiar ion mobility device, combining a flow field U andan electric field E between two electrodes. Only the ions with a well defined electrical mobility aretransmitted into an outlet slit leading to the device detector

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BENCHMARKING vs. IMS DRIFT TUBE

DMA DRIFT TUBE (STANDARD IMS)

Filtration of ions

Continuous (space-filtrated, duty cycle 100%)

Discontinuous(time-filtrated, duty cycle ≈ 1%)

Ion transmission

50% ≈ 0.1%

Resolution(peak voltage/FWMH)

> 110 ≈ 10

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BENCHMARK AGAINST OTHER DMAs

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DIFFERENTIAL MOBILITY ANALYZER

• Solid model of the planar (termed DMA P5 model)

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• Choose your favourite DMA configuration (includes real use cases by customers)

DIFFERENTIAL MOBILITY ANALYZER

STAND ALONE USE

(for mobility classification of particles and molecules)

AS A FRONT END OF MASS SPECS

(for Mobility-Mass 2D studies)

TANDEM DMA

(for nanoparticle process studies)

OR GO DIRECTLY TO OUR RELATED PRODUCT CATALOGUE

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• DMA working as an Add-on for your favourite mass spectrometer

MOBILITY FRONT END – OVERVIEW

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Atmospheric research Proteomics Food Control Atmospheric nanoparticles nucleation Liquids and vapours

Ion source + DMA

DMA coupled to a Bruker MS

Mobility Front End main elements: exploded view

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FRONT –END:ARQUITECTURE AND OPERATION

ArquitectureThe Front End has been developed as a compact unit and equipped with the latest proprietary ionization and mobility technologies

PC

MSIonization chamber

N2

Sheath Gas flow

Sample/ion pathElectrical/Electronic connections

Electronics Rack

Sample inlet

gas /liquid

Exhaust

USB

Ionizationchamber

Low Flow SESI (LFSESI),which can be used as a vapor charger for gas samples, or operated as a nano-ESI for liquid samples. Our newest D_LFSESI source provides even enhanced performance for vapors avoiding solvation of ions.

Differential mobility analyzer

(DMA)

Planar, supercritical type.

Massspectrome

ter

A range of SoTA systems can be coupled (see specification sheet for details).

Electronics and

controls

The electronics rack is controlledby the operator's software. It fixesthe HVDC references for the DMAand the ionization chamber. Itaccurately controls thetemperature of the key elements(DMA recirculation circuit,ionization chamber), and providesthe necessary flows at a controlledpressure for stable operation.

DMA

Pump

Electronic controls rack

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MOBILITY FRONT END: USER CASE #1, PROTEOMICS

• Hogan C.J. Jr“Tandem Differential Mobility Analysis-Mass Spectrometry Reveals Partial Gas-Phase Collapse of the GroEL Complex”J Phys Chem B. 2011; 115(13); 3614-2361.

In this study, SEADM’s Mobility FrontEnd was applied to measure true mobility ofGroEL tetradecamers (14-mers; ~800 kDa).Narrow mobility peaks were found (2.6-2.9%FWMH); hence, precise mobilities wereobtained for these ions without collisionalactivation, just following their generation byelectrospray ionization. Interestingly, twoconformers were found with mobilities (Z)differing by ~5% at charge state z ~ 79.Following analytical study, it was concludedthat the gas-phase structure of the GroELcomplex as electrosprayed is substantiallymore compact than the corresponding X-raycrystal structure.

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MOBILITY FRONT END: USER CASE #2, ATMOSPHERIC SCIENCE

• Ouyang et Al. “Investigation of the structure and stability of dimethylamine-sulfuric acid nanoclusters”J. Phys. Chem. A 2015, 119, 2026−2036

Results shown on the left: Mass-mobility contour plot inferred fromDMA−MS measurement of multiply chargeddimethylamine-sulfuric acid nanolcusters,with measured signal intensity expressed viacolor intensity on a logarithmic scale, withblue the most intense and yellow the leastintense. Bands of ions of different chargestates are labeled, from z = 1 to 7.

This study clearly showed that nanoclustersof dimethylamine-sulfuric acid uptake waterat relative humidities beyond 10% near 300K, and that larger clusters uptake water to alarger extent

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• Maisser et Al. “Heterogeneous vapor uptake by single atom ions of both polarities using a differential mobility analyzer – mass spectrometer (DMS-MS) ” European Aerosol Conference, Sept-2016, Tours, France

“The results show that even for single atom ions the initial size ofthe seed influences the uptake rate. While the Kelvin-Thomsonmodel can predict the expected shifts with satisfactory accuracyfor positive ions, the current model fails to correctly predict thedependencies of uptake rates on size, charge and vapor polarityfor single atom ions”.

MOBILITY FRONT END: USER CASE #3, ATMOSPHERIC SCIENCE

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• System main modules:

STAND-ALONE DMA: NANOPARTICLE AND MOLECULE CLASSIFIERS

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Atmospheric studies Production of nanoparticles Biomedical / health Atmospheric science Nucleation and reaction kinetics

ELECTROMETERDMAESI

• Applications:

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≈ 1-2 minutes

STAND-ALONE DMA: ARQUITECTURE AND OPERATION

DMA

Pump

Ionizer (ESI)

Gas / Aerosol

Liquid / charging solution Monodisperse

mobility sample

Vial holder

Polydispersemobilitysample Vaccum

pump

PC – based user interface

Electrometer

Pump Intercooler

Control rack

CONSTANT VOLTAGE Nanoparticle selected in size.

(Given the relation mobility-size)

SWEEPING VOLTAGE Nanoparticle characterization (size-

spectrum)

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STANDALONE DMA - PERFORMANCE

HALF MINI Range sub-1 nm to 30 nm Resolution 30 1/FWMH Relative easy manufacturing

DMA P5 Range one atom to 5 nm Resolution > 110 1/FWMH Ultra high transmission

Laminar flow at Re > 200,000 → Diffusion broadening minimized → Resolution maximized

• Nanoparticle and molecule classifiers with optimum resolution

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• Wang et Al. “Application of Half Mini DMA for sub 2 nm particle size distribution measurement in an electrospray and a flame aerosol reactor” Journal of Aerosol Science 71 (2014) 52-64

STANDALONE DMA: USER CASE #1

ESI

200 µM THAB in methanol

Nano-DMA (TSI, U.S.A.)

BENCHMARKINGSTUDY

SEADM’s Half Mini

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Resolution almost 3 times larger than the reference instrument

STANDALONE DMA USER CASE #1

Journal of Aerosol Science 71 (2014) 52-64 17

• Wang et Al. “Application of Half Mini DMA for sub 2 nm particle size distribution measurement in an electrospray and a flame aerosol reactor” Journal of Aerosol Science 71 (2014) 52-64

STANDALONE DMA: USER CASE #2

Nano-DMA (TSI, U.S.A.)

BENCHMARKING

Journal of Aerosol Science 71 (2014) 52-64

SEADM’s Half Mini

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STANDALONE DMA: USER CASE #2

Characteristic ion peaks below 2 nm were detected →clusters below 2 nm with high resolution. Further help examine the initial stage of particle formation

Journal of Aerosol Science 71 (2014) 52-64 19

• Wang et Al. “Kinetics of sub-2 nm TiO2 particle formation in an aerosol reactor during thermal decomposition of titanium tetraisopropoxide” J Nanopart Res (2015) 17:147

STANDALONE DMA: USE CASE #3

J Nanopart Res (2015) 17:147 20

TANDEM DMA (TDMA)

SEADM’s Tandem Differential Mobility Analyzer (TDMA) enables to study a wide range of nano-aerosol processes by analyzing the change of electrical mobility experienced by thenanoparticles.Electrical mobility is a well-proved method to elucidate structural and size characteristics ofions, and has been successfully applied for the study of processes such as evaporation,condensation, chemical reactions, charge reduction (or charge evaporation), nucleation, etc.

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Figure 1. 2D continuous DMA2 spectra of multiply charged aggregates of polystyrene. V1 and V2 are, respectively,in the horizontal and vertical axes. Number of monomers range from n=1-4. Charge loss is indicated as superscript.Note the high signal region at V1≈1630 V, corresponding to a constant mobility of 0.23 cm2/V/s

Figure 2 Complex cluster pattern formed on electrospraying a solution of an ionic liquid with structure [A+B-]. Each of thesharp peaks seen is associated to a cluster (AB)n A +

z . The main series of peaks in the diagonal line is associated to ionsundergoing no changes between both DMAs. The small peaks to their right result from evaporation of a single saltmolecule, whereas peaks to their left order themselves in various lines associated to various levels of charge loss.

Figure 1 below shows an application of the TDMA principle for the characterization monodisperse polystyrene particles formedby electrospraying a concentrated solution of Psty-34.5k and partially neutralized by a radioactive source. Observed chargestates are unusually low relative to previously studied water-soluble polymers. The study revealed that large particles areoriginally charged in such a fashion as to give an almost constant mobility (in air) of 0.23 cm2/V/s, implying a critical electricfield for ion evaporation from a polystyrene sphere of around 0.7 V/nm.The use of SEADM’s TDMA system has also been applied for the generation of monomobile molecular standards at 1-3.5 nmsize range, by means of electrospray followed by DMA, a process that is usually hindered by the formation of many clusters indifferent charge states z in a narrow mobility range. The TDMA proved to be uniquely useful, since many of the multiplycharged ions selected in the DMA1 undergo spontaneous transitions, appearing as pure species at different mobilities in DMA2(Figure 2).

TANDEM DMA (TDMA)-APPLICATION EXAMPLES

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• F. Carbone (University of Yale) Interesting range: 1-50 nm

"The Half Mini DMA is a robust and user friendly instrument that has also a goodconfiguration flexibility allowing to personalize the measurements strategy. Thepossibility of classifying even small ions offered by the instrument is greatly beneficial tounveil the mechanisms of particle nucleation even in challenging environments such assooting flames“.

OUR CUSTOMERS REVIEW

• A. Maisser (University of Vienna) Interesting range: sub-nm

"All ions measured had sizes in the sub nanometer range and thus other commerciallyavailable ion mobility spectrometers that operate at atmospheric pressure would nothave met our needs in terms of resolution or transmission. This enabled experiments ata new level of accuracy and precision”.

Click to access Dr. Carbone’s full work

Click to access Dr. Maisser’s full work23

PRODUCT RANGE

Differential Mobility Analyzers http://www.seadm.com/products/nano-particle-and-molecule-classifiers/

Full system: vapour analysis system http://www.seadm.com/products/vapour-analysisdetection/vapor-analysis-system/

Low noise, ultra-fast response electrometershttp://www.seadm.com/products/technological-modules/electrometer/

Ionization sources (including bipolar ionization source for the study of atmospheric clusters)

http://www.seadm.com/products/technological-modules/ionization-sources/

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SEADM

Rafael CuestaBusiness Coordinator

rafael.cuesta@seadm.comT. +34 687 503052

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